Theresa May has spoken of her shock after being diagnosed with a chronic illness, but insists it will not affect her political career.

The Home Secretary was diagnosed with Type 1 diabetes two months ago and must now inject herself with insulin at least twice a day for the rest of her life, the Mail On Sunday revealed.

Commentators had seized on Mrs May's dramatic weight loss over the past 18 months as proof that she was undergoing a style makeover in preparation for a future leadership bid.

But the Conservative Cabinet minister told the newspaper that dropping two stones was partly down to the illness.

"The diabetes doesn't affect how I do the job or what I do. It's just part of life ... so it's a case of head down and getting on with it," Mrs May told the Mail On Sunday.

"It was a real shock and, yes, it took me a while to come to terms with it."

There are around 300,000 people in the UK with Type 1 diabetes

Speaking about the timing of the announcement, Sky's chief political correspondent Jon Craig said: "I suspect she wanted to get the Abu Qatada deportation out of the way and wanted nothing to distract from that."

There are around 300,000 people in the UK with Type 1 diabetes. Despite decades of research, no vaccine has been found to prevent the disease.

Pressed on whether the illness would prevent her from one day succeeding David Cameron, she told the newspaper: "There is no leadership bid.

"We have a first-class Prime Minister and long may he continue."

Doctors told Mrs May she had the condition, which means her body does not produce insulin, in November but initially they thought she had Type 2 diabetes.

"It doesn't and will not affect my ability to do my work. I'm a little more careful about what I eat and there's obviously the injections, but this is something millions of people have," she said.